As the United States expanded across the Mississippi River, mail delivery proved to be a challenge. Mail carried by stagecoach or steamship took over a month to get to California. For a time, there was the Pony Express, which boasted famous riders like Buffalo Bill Cody and Wild Bill Hickock, that could carry mail from St. Joseph, Missouri to Sacramento, California in only ten days. A lesser-known Pony Express route traversed Dakota Territory, but the first winter put an end to it. The southern route didn't last much longer, running from April, 1860 to October, 1861.